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A Contractors Update
on Full Depth
Reclamation
FDR
Presented to APWA Annual Conference
Barry McKeon
Technical Manager
Hubbard Construction Company
April 2013
Presentation Outline Introductions / Brief Overview of The Hubbard Group
Common Types of Asphalt Recycling
FDR (Full Depth Recycling)
The Process
The Advantages
CIR (Cold In-Place Recycling)
Equipment Overview
Project Applications
Contractors Quality Control
Economic & Environmental Benefits
Conclusions
Common Types of Roadway Recycling in the
US
Hot Recycling (HR) Hot Mix Asphalt (HMA)
Hot-In-Place Recycling (HIR)
Full Depth Reclamation (FDR)
Cold-In-Place Recycling (CIR)
Cold-In-Plant Recycling (CIP)
The Hubbard Group are Members of the
Asphalt Recycling & Reclaiming Association arra.org
Full Depth Reclamation
FDR
FDR- 6”–12” blend of asphalt and
base materials
Full Depth Reclamation (FDR)
Cold Full-Depth Reclamation (FDR)
Full-Depth Reclamation is an
economical, recycling technique in
which the full flexible (asphalt)
pavement section and a portion of
the underlying base materials are
uniformly pulverized, blended and
then stabilized with a bonding
agent
Typically Utilizes 1.5% - 3.5%
emulsion or foamed asphalt
material as a bonding agent.
Cement can also be used to
enhance bitumen, modify soils to
CBR/LBR or produce Soil Cement
(Rigid Base).
Others- Fly ash, Lime…..
The FDR Process
Advantages
Uses 100% of existing materials – Extremely GREEN process.
Eliminates Cracks and Resists Future Fatigue Cracking.
Much quicker than traditional base reconstruction methods.
Load bearing strength of existing base section can be increased.
More Advantages
Very effective on projects requiring widening.
longitudinal re-profiling and grade correction can be accomplished.
Cross slope corrections can be realized.
Base courses constructed using the FDR process can result in more moisture tolerant base courses.
Moisture Susceptibility
Florida Limerock FDR with 3% emulsion
Cold-In-Place
Recycling
(CIR)
CIR Equipment
CIR: 4”-6”, 100% Asphalt, on well supported base.
Creates new asphalt base layer.
FDR: 6” – 12” blend of asphalt and base material.
Creates new base structure layer.
CIR vs. FDR – “What’s The
Difference?”
Recycled Materials at Auger
Recycled material at Auger before screed, well mixed and well graded material
CIR Finished Surface
Recycled Material Surface Finish / Mix
FDR Equipment Overview
Pulverizing, Injection & Stabilization:
Wirtgen 2500 S Cold Recycler & Stabilizer.
2 Pumps with 2 Spray Bars – 1 for emulsion (or water) & 1 for foam.
Capable of Cold FDR with Emulsion or Foam injection.
Drum width = 8’
Cutting Depth: Up to 20” depth.
TEREX Reclaimer
Cutting & Injection
No Cross Mixing
Transferring & Monitoring Materials
Steering Considerations
Recycling Train
2009/10 FDR Field
Application
County Road 609
Martin County, Florida
Existing Roadway Conditions
Initial Pulverization & Widening
Widening Trench
Shaping & Compacting
Elevation Changes Required by
Plans
18”
Injection of Emulsion
Existing Material with 2% Emulsion
Injected
Final Grading & Compaction
Primed FDR with Temporary Stripes
2.5” Superpave HMA Overlay
Other overlay options for rural applications:
- Double Chip Seal
- Cape Seal
- Micro-surfacing
Average recycling speed for the
project 27.5 ft/min.
This average speed at a depth
of 6 ins and a width of 12.5ft
equates to an hourly recycling
tonnage of 610 tons per hours.
Application & Production
Average Depth: 7”
Emulsion Content = 2%
Daily average production:
Pulverization -8,000 SY / Day *
Emulsion Injection – 5,000 SY / Day
All materials were metered electronically by the machine.
* 2 WR 2500’s in Tandem
FDR Project Overview – CR 609 in Martin
County
Total Contract Price:
$2,117,145.96
Length: 9.2 Miles (18.4 Lane
Miles)
Completion Time: 60 Days
Bumby Avenue Full Depth
Reclamation Project
City of Orlando, Florida
Bumby Ave. Project Description
Heavily traveled urban roadway on the east side of Downtown Orlando
Approximately 4,800’ long x 60’ wide (5 Lanes) = 32,000 Square Yards
18,000 square yards existing soil cement base
14,000 square yards existing lime rock base
Curb and gutter & utilities throughout project
Work to be performed in 9 phases due to City’s concerns:
Impact on businesses
Experience with previous contractors
Contract time = 180 Calendar Days
All work performed during normal business (daylight) hours
Project
Location
Description of Work:
Pulverize 11” of existing base and pavement
Remove 3” of material from site
Inject remaining 8” with emulsion
Grade new materials to 2% cross slope matching curb & utilities
Prime and sand new base
Allow 48-hour cure
Overlay with 3” SuperPave Hot Mix Asphalt
2” 12.5 TL-C structure course
1” 9.5 TL-C surface course
New pavement markings
Completion of FDR & HMA Work
Bumby Avenue, City of Orlando
Contract time allowed 180 Calendar
Days
All structural asphalt completed 83
Calendar Days / 51 Working Days
Plymouth Ave.
20,146 Square Yards
High Traffic Volume
Asphalt from 8” to 2”
Base Materials – Lime Rock
and Snail Shell
2 Mix Designs
Soil Cement
Volusia County 2012
Carlton Avenue
Douglas Avenue
Forest Avenue
Howry Avenue
Volusia County
5,756 Sys Total – Residential Area
Low Traffic Volume
Stevens Avenue
3,200 Sys – Residential Area
Low Traffic Volume Asphalt Thickness: 1.5” to 2.5”
Cement Spread Rate: 15lb/SY
Base Material: Clayey Sand
RMI Cement Spreader
Volusia County Projects
2012
Minnesota
Avenue
Volusia County 6 Foot Widening
Excess Lime Rock Material
from Plymouth
Blended into Existing Base Asphalt Thickness: 1.5” to 2.5”
Cement Spread Rate: 15lb/SY
Base Material: Clayey Sand
Uniform across new 22’
width
Minnesota Ave
Before and After
Minnesota
Avenue
Downtown Tampa
Cores and Mixer Sample
Good base under very thin asphalt did not require any additive.
Desoto Memorial Hospital
Before
Resurfaced with Double Chip and Cape Seal
Pre-Mixing and Re-Grading
Cement Spread
Mixing and Compacting
Checking Gradation of Pre-Mixed
Materials
LBR Samples
Roadway Surfaces Favorable For In-Place
Recycling
Block Cracking
Caused by insufficient asphalt thickness,
weak structural base, heavy traffic & aging
roadway
Minor Rutting
Caused by insufficient thickness of asphalt,
poor asphalt mix design formulation,
improper compaction methods or heavy
traffic
Major Rutting
Caused by very heavy traffic conditions,
deficient structural capacity, deficient
compaction or deficient drainage conditions
Block Cracking Minor Ruts
Major Ruts Ravelin
g
Materials and Mix Design
Marshall Stability Tensile Strength
Specifications & References for Mix Design Procedures
The Wirtgen Cold Recycling Manual
Published in many languages &
utilized all over the world.
Other Primary References:
ARRA Basic Asphalt Recycling
Manual
Asphalt Institute – Asphalt Cold Mix
Manuals (MS 14 and MS 19)
PCA Soil Cement Laboratory
Handbook
Mix Design Methods for FDR
Laboratory Mix Design Methodology:
Steps Required for Mix Design Development:
Cut cores or exploration windows to obtain representative materials
Pulverized materials for gradation characterization
Binder selection (emulsion or foam usually required by contract
specifications)
Determine optimun water content
Determine optimun asphalt binder determination
Determine optimun cement/lime binder content (if needed)
71
Sampling
Obtaining Materials for Design
Requirements
Perform enough cores to
determine if variables exists
Depending on size of area &
known base types, cut or mill
windows to obtain
representative samples needed
to prepare mix design(s)
Documentation of Existing Roadway
Conditions
Existing Asphalt Ranged
From 2.5” to 6” deep.
Avg Depth = 4.5”
Mix Design Considerations
Mix Design Methods
Modified Marshall Stability (Asphalt Inst. or ARRA)
Tensile Strength (Wirtgen)
Compressive Strength
(Soil Cement) (PCA)
CBR/LBR (AASHTO/FDOT)
(Cement Modified)
Laboratory Mix Design Methodology
Binder Options In-Place Recycling Processes:
Asphalt binders
Asphalt emulsion (CSS-1, CSS-1H, SS-1 et CMS-
2)
Foamed asphalt (usual grade without silicone )
Hydraulics agents
Cement
Hydrated lime
Composites binders
Asphalt emulsion + Cement
Asphalt emulsion + Hydrated lime
Foamed asphalt + Cement
Foamed asphalt + Hydrated lime
Pre-Bid Information
Client Provided Core Information
Client Provided Mix Design Criteria
Client Provided Additive Pay Items
Client Provided Contractor Quality Control Requirements
Quality Control Best
Practices for Full Depth
Reclamation
Barry McKeon, Technical Director
RMI/Hubbard Construction Company
Contractor Project Specific QC
Plan Description of process i.e.…FDR
Project Assessment and Site Investigation
Sampling and Mix Design
Mixing Equipment and Mixing Operations
Spreading Finishing and Compacting
Priming and Curing
Quality Control
Speedy Moisture Content
Early verification of
moisture content
Monitor throughout the
operation and adjust as
needed
Moisture content by nuclear gauge can not be used when RAP is present
Quality Control During Field Operations
? Why is Moisture Content Important?
2 Reasons
Coating and Compaction
Pre Mixing for Widening or Cross Slope
adjustments
Sampling Full Depth of Mixture
Check for Depth
Uniformity
Gradation
Maximum
Size (95% pass
2”)
Samples for
Check Cross Slopes
Compaction
Nuclear Density Tests
Establish Control
Strip
Wet Density
96% Min
Prime and Cure
Always apply
Bituminous Prime
Protects base from
weather
Holds better under traffic
Provides bond to new
surfacing (HMA, Chip,
Micro)
Cure Time to Reduce
Environmental Advantages of In-Place Recycling
Methods
Removal of trucks hauling materials to and from the project greatly reduces
congestion associated with traditional road rehabilitation projects.
Shorter construction duration & reduced equipment requirements enhance
project efficiencies & reduce fuel and energy consumption at the project site.
Elimination of the energy inputs in the manufacturing process of producing
aggregates and hot mix asphalt.
Reduction of Greenhouse Gas Emissions .
Besides the advantages to the environment, agencies also realize significant
cost savings of at least 30% associated with reduced equipment,
transportation, and labor costs
Conservation of Natural Resources & Energy
Agencies are look into more “green strategies” FHWA “Think Recycle First
and Always”
FDR offers the ideal sustainable strategies since they utilize 100% of existing
materials and require up to 80% less energy per ton as compared to hot mix
overlays, or conventional construction.
These numbers are greatly significant when designers are evaluating a
sustainable strategy for a project.
Thus, in-place processes not only provide a sustainable strategy but they also
provide a pavement section at a lower initial cost.
Reduction of Energy Use
.
The energy expended for both the traditional
Hot Mix Asphalt process, and the proposed
CIR technology.
Summary & Conclusions:
Both FDR & CIR are FHWA approved processes that have been successfully
utilized around the globe for about 15-20 years.
Environmentally, the use of the in-place recycling processes on local projects
would reduce the consumption of significant natural resources & savings
could allow for funding of additional miles of roadway maintenance.
The use of in-place recycling processes has the potential to significantly
reduce the time required to complete local reconstruction projects, while
minimizing inconvenience to the public.
Would you like additional information?
The Asphalt Recycling & Reclaiming
Association (ARRA) is a great
resource for additional information
related to CIR & Full Depth
Reclamation:
Website:
www.arra.org
Thank You Very
Much!
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